What is Spondylolisthesis?
Written by Neil Badlani, M.D., Chief Medical Officer, North American Spine

In Spondylolisthesis, the fracture along the pars interarticularis completely separates, which allows the affected bone to slip forward, causing it to shift down to the bone below it, by passing the cushion of the disc. In adolescents, it is most common to experience this sort of slippage during the periods of most rapid growth, like during a growth spurt in the teenage years. 

Spondylolisthesis is the condition that occurs when the stress fracture causes the vertebrae to become so weak that it can no longer support itself in its position along the spine. This leads to the bone shifting or slipping away from its spot and onto another bone, likely causing pain. 

In most cases, either condition can and will improve even if you stick to conservative treatment. This means avoiding the sport causing the problem as well as any other strenuous activities for a while. If the bone has slipped very far or results in consistent, serious back pain, then surgery could be required to alleviate the pain.

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More About Spondylolisthesis

lumbar foraminotomy

Twenty-four small bones known as the vertebrae make up the whole length of your spine, and these rectangular bones stack on top of each other. The canal they form serves as a protective house to keep the spinal cord safe and intact. The five lower back vertebrae that can be affected by these conditions are the lumbar spine.

Other spinal regions include:

  • Intervertebral discs: Between each spinal bone are the cushiony shock absorbers that withstand the impact of your movements as you walk, run or perform other every day exercises. 
  • Facet joints: Between the back of the spinal bones are the facet joints, which help the spine move freely and stably. Think of them like hinges, running down the full length of the spine on either side in pairs. 
  • Spinal cord and nerves: These are the cables traveling along the spinal canal that carry the sensitive messages between the muscles and the brain. The canal also has several nerve roots that branch out, exiting through vertebral openings.


What are the symptoms?

For the most part, there are no obvious symptoms for those who experience spondylolisthesis, such that you may not even realize you have it until you have to take an x-ray for a different condition or injury. 

Should symptoms manifest, lower back pain is the most common one to experience. It is possible the pain will:

  • Feel like a muscle strain 
  • Get worse with activity, and get better with rest 
  • Spread down to the back of the thighs and the buttocks

When the fracture splits and results in spondylolisthesis, muscle spasms can occur, putting pressure on the spinal canal near the split, ultimately resulting in further symptoms like:

  • Tight hamstrings 
  • Stiffness in the back 
  • Difficulty walking or even standing 
  • Numbness, weakness, or tingling in one or both legs in those with severe vertebral slippage

How is a Spondylolisthesis Diagnosed?

The first indicator of spondylolisthesis is pain. If you have pain, your doctor will do a couple things to determine if you have spondylolisthesis:

Medical History

Your doctor will begin the process of diagnosis with an interview about general health history and the symptoms currently experienced. Those who play sports that strongly stress the lower back are at the highest risk of developing a spinal fracture and spondylolisthesis.

Physical Examination

After this, your doctor will then need to closely examine your spine directly, specifically checking for:

•  Muscle weakness 

•  Muscle spasms 

•  Limited range of motion 

•  Tender areas

Diagnostic Imaging

Imaging tests will assist with confirming the suspicion of spondylolisthesis; most commonly, a doctor will order an x-ray. This is a test that allows doctors to look inside dense bone. The doctor may opt for multiple angles to verify a stress fracture and to test the vertebral alignment.

What are the causes of a Spondylolisthesis?

low back pain

Several conditions can cause spondylolisthesis. For example, it’s possible to be born with a defective vertebra, or it may simply develop a stress fracture or break from trauma. Additionally, disease or infection can cause the vertebrae to wear down over time. Potential causes of spondylolisthesis include: 

As may be suspected, spondylolisthesis most often occurs when the spine is overused; specifically, it occurs when young children and adolescents frequently hyperextend their spines in high-impact sports. Participating in sports like weight lifting, gymnastics, and football can lead to weakness and fracture in the pars interarticularis, as well as vertebral slippage. 

Some people are simply born with thinner vertebral bone than others are, which naturally makes them more likely to develop fractures as the bones lack stable 

How is Spondylolisthesis treated?

Conservative Options

Conservative treatment options include nerve root blocks and steroid injections. These are designed to provide temporary relief (up to one year), and you may elect to have the procedure done multiple times. Other conservative strategies may include the placement of a spinal cord stimulator–or STIM–which is designed not to correct the underlying degeneration, but to lessen the pain the condition causes.


Minimally invasive decompression surgery aims to relieve pressure on the nerves of the spine. This pressure is often caused by stenosis, bulging or herniated discs, and more. Relieving this pressure can be achieved by reducing or removing soft tissue (disc material or scar tissue) or bone (bone spurs, a section of the lamina or foramina) to decompress the affected nerve. When the compression is caused by soft tissue material, a surgical laser may be used to shrink the impinging material.


Fusion surgeries are similar in goal–to remove damaged disc tissue and fuse the bones together–but differ in approach, including the use of specialized hardware to reinforce stability, and the location used to gain access to the spine. A related procedure is an artificial disc replacement, in which a damaged cervical disc is replaced with a synthetic disc, and the vertebrae are not fused.

How Much Does Treatment Cost?

Treatment cost depends on several factors, especially what insurance you have and how much of your deductible has been met. In the previous two years, 90% of our patients have paid less than $2000 out-of-pocket. Some have paid literally nothing, and other have paid much more than that. It depends. The good news is: our Patient Care Managers will handle as much as they can directly with your insurance company, and all your costs will be known up-front.

Important note: spine surgery often pays for itself within a year or two. Many people actually spend more money trying to live with the pain than they do getting the pain fixed. The following calculator is intended to give you a sense of what you spend on managing—rather than eradicating—your pain.

Equipment Used in Diagnosis and Treatment of a Spondylolisthesis

Computerized tomography (CT) scan: This is more complex than a single x-ray, though it is much like one. Instead, it takes pictures from multiple angles and uses a computer to generate a single, detailed image for your doctor, who can use this to check for slippage. 

Magnetic Resonance imaging (MRI) scan: Because an x-ray and a CT scan can only provide images of bones and such structures, an MRI scan can assist your doctor with checking the soft tissues in the region. This is important to see if there is a damaged disc between the slipped vertebrae, or if there is pressure on the spinal cord or its nerve roots. This can also reveal injury to the pars before a fracture appears on an x-ray. 

If surgery is necessary to treat the spondylolisthesis, then the most likely procedure is a spinal fusion between the sacrum and the fifth lumbar vertebra. 

The goals of spinal fusion surgery are:

  • Stabilizing the spine 
  • Reducing serious pain in the back 
  • Stopping the slip from getting worse

How Does Spondylolisthesis Compare to Other Spine Conditions?

As previously mentioned, spondylolisthesis is similar to spondylolysis, though they are different conditions.  

Spondylolysis may happen in patients of all ages, but children and adolescents are the most vulnerable because their spines have not finished developing and are susceptible to early wear and tear. Many times, spondylolysis patients have some form of spondylolisthesis. 

If it is not treated correctly, spondylolysis weakens the bone so much that it cannot maintain its place in the spine, leading to the slippage known as spondylolisthesis.

  • Collapsed Disc
  • Herniated Disc
  • Herniated Nucleus Pulposus (HNP)
  • Slipped Disc
  • Disc Extrusion
  • Disc Protrusion
  • Pinched Nerve
  • Compressed Nerve

A slipped disc is another condition that can occur that mimics the symptoms of spondylolisthesis, especially if the disc has pinched a spinal nerve root. Injury or weakness to this spinal cushion can result in the gelatinous’ interior to leak through cracks along the outer ring of the disc. 

Symptoms of a herniated disc include a similar feeling of pain, numbness, tingling, and weakness, especially if the disc that slips does so in the lower lumbar region of the spine. This is why it is important to speak with your doctor and discuss all of your symptoms–to get the right diagnosis and treatment.

Analogy: A Stack of Onion Rings

Imagine you order a stack of onion rings. Often, the restaurant will stack the rings on a little pole so they don’t slide all over the plate and create a mess. It’s a neat, orderly system. The onion rings are like your vertebral discs. If one of them falls over the one below it, the order will be ruined and the plate—and your spine—could become a mess.

Surgery will focus on getting that disc back where it is supposed to be, or removing part of the material that is hanging over the disc below it.

A Neat Stack of Onion Rings


A Messy Stack of Onion Rings


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